docs(python): Small clarifications in the contributing guide (#14310)

docs/development/contributing/index.md

@@ -227,7 +227,7 @@ From the `py-polars` directory, run `make fmt` to make sure your additions pass
 
 Polars uses Sphinx to build the API reference.
 This means docstrings in general should follow the [reST](https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html) format.
-If you want to build the API reference locally, go to the `py-polars/docs` directory and run `make html SPHINXOPTS=-W`.
+If you want to build the API reference locally, go to the `py-polars/docs` directory and run `make html`.
 The resulting HTML files will be in `py-polars/docs/build/html`.
 
 New additions to the API should be added manually to the API reference by adding an entry to the correct `.rst` file in the `py-polars/docs/source/reference` directory.

docs/development/contributing/test.md

@@ -30,7 +30,8 @@ Slow tests are marked as such using a [custom pytest marker](https://docs.pytest
 If you wish to run slow tests, run `pytest -m slow`.
 Or run `pytest -m ""` to run _all_ tests, regardless of marker.
 
-Tests can be run in parallel using [`pytest-xdist`](https://pytest-xdist.readthedocs.io/en/latest/). Run `pytest -n auto` to parallelize your test run.
+Tests can be run in parallel by running `pytest -n auto`.
+The parallelization is handled by [`pytest-xdist`](https://pytest-xdist.readthedocs.io/en/latest/).
 
 ### Writing unit tests
 

py-polars/tests/unit/io/test_delta.py

@@ -388,7 +388,7 @@ def test_write_delta_with_merge_and_no_table(tmp_path: Path) -> None:
 def test_write_delta_with_merge(tmp_path: Path) -> None:
     df = pl.DataFrame({"a": [1, 2, 3]})
 
-    df.write_delta(tmp_path, mode="append")
+    df.write_delta(tmp_path)
 
     merger = df.write_delta(
         tmp_path,
@@ -407,8 +407,7 @@ def test_write_delta_with_merge(tmp_path: Path) -> None:
 
     merger.when_matched_delete(predicate="t.a > 2").execute()
 
-    table = pl.read_delta(str(tmp_path))
+    result = pl.read_delta(str(tmp_path))
 
-    # TODO: Re-enable row order check after issue is resolved:
-    # https://github.com/delta-io/delta-rs/issues/2165
-    assert_frame_equal(df.filter(pl.col("a") <= 2), table, check_row_order=False)
+    expected = df.filter(pl.col("a") <= 2)
+    assert_frame_equal(result, expected, check_row_order=False)